Cleaned up some warnings in the codebase.

API/Program.cs

@@ -1,11 +1,8 @@
 using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Threading.Tasks;
 using API.Data;
 using Microsoft.AspNetCore.Hosting;
 using Microsoft.EntityFrameworkCore;
-using Microsoft.Extensions.Configuration;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Hosting;
 using Microsoft.Extensions.Logging;